Every time ________ they met , they would talk several hours together about the persons and things ________ they remembered in the middle school．
A.that; who and whichB.when ; whichC./; thatD.which;/在线课程C
解析：
本题考查定语从句。第一空中由于every time用在句中作连词，所以这里不需要关系词；
第二空考查定语从句，先行词是persons and things，即指和物，在从句中作动词remember的宾语，故关系词只能用that。句意：每次他们见面的时候，他们都将花几个小时在一起谈论在中学时他们记得的人和事。